In this May 8, 2014 file photo, an obese person is seen in New York. (AP Photo/Mark Lennihan, File)

(Newser)
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Stool transplants already appear to be helping fight the hospital-acquired superbug C. difficile, and they're also being tested against ulcerative colitis and Crohn’s disease. But could the radical treatment go so far as to help obese people shed weight and not gain it back again? Researchers at the University of Toronto are investigating the effect of and mechanism behind fecal transplants as part of a $1.5 million project, reports Canada's National Post. Gut bacteria have already been shown to be different between thin and obese people. "If you, who are skinny, and I, who is a little fatter, eat the same amount of food, you’ll suck up less nutrients and I’ll suck up more. Part of the reason is because my bacteria metabolizes the food in a way that I’ll suck up more," one researcher explains to Vice.

Reporting in the journal Nature Genetics, researchers say that by analyzing more than 1,500 healthy participants they've found four key genetic markers associated with gut microbiome changes—which hints at genetics, not merely diet, playing a role in our gut flora. Next they plan to study mice and even do a very small fecal transplant trial in humans. But, they caution, "You’re taking a donor at random and just hoping the donor has the right microbiota based on the fact they’re not obese," notes the lead author. Another researcher points out that a skinny person could be predisposed to other health problems, like cancer. Researchers also warn the subject area is very new: "We haven’t learned to walk yet and we’re starting to run," the lead author adds, pointing out that fecal transplants could theoretically induce obesity or other diseases. (It's taking some work to engineer the fecal capsule itself.)